When her teenage son is jailed for murder in Bulgaria, flight attendant Jo enters a murky world of drug smuggling and will stop at nothing to save him.
After a fight outside a bar, 19-year-old Sonny Conran is arrested and charged with a murder. His mum Jo rushes to Bulgaria, but Sonny's lawyer warns Jo that the police have already made up their minds. Jo focuses on proving Sonny's innocence.
Left with no choice but to continue Cormac's international drug runs, Jo turns to her ex for help. Following a close call with the police, Jo is forced to quickly secrete heroin in the airport, but it goes missing. She has 24 hours to get it back.
Jo rushes to Sofia when Sonny is stabbed in prison. Elsewhere, having enlisted the help of his former police partner, Shana, Dom is told that the Met have zero intel on Cormac. Jo returns home to a surprise visitor who delivers some shocking news.
Dom warns Jo that Cormac is extremely dangerous but she ignores his advice and follows him to a meeting with an unknown boss. A veiled threat makes Mel suspicious and a new witness comes forward in Sonny's defence - although things do not go as expected at the appeal hearing. Jo is told to run - but instead, she and new ally Kayla come up with a new plan.
After stealing the heroin and money, Jo realises Cormac is also being blackmailed, so they collude to get out for good. Smuggling more heroin, they sell it on, while Cormac puts things in place for Jo's escape. Kayla gives birth, and Shana reveals to Dom that Cormac's boss is Anton Marquis - a senior police officer.
Jo demands answers and finally uncovers the truth in Sonny's case. She and Cormac execute their escape plan, though she remains uneasy as to whether he can be trusted.
